dovecot 2.3.19.1 + tika-server 2.4.1 failed attachment scanning -- ERROR: 'corrupt stream'?

i'm running dovecot 2.3.19.1 + fts_tika for attachment scanning, with tika-server 2.4.1

submitting a PDF attachment DIRECTLY to tika, via curl, there's no issue -- scan's OK

on mail receipt in dovecot, the attachment is submitted to tika via fts, but scanning fails with a 'corrupt stream' ERROR.

i've posted the issue, with details here, @ tika ML,

https://lists.apache.org/thread/pztsq8tb8xqz3s4kmjpnt9p3zt07y05k

where it's suggested the message may be getting truncated

since direct-via-curl doesn't truncate, it seems that the submission process -- via fts plugin -- is a possiblity.

can anyone confirm PDF attachment scan in a similar config, with latest versions?

or suggest what diagnostic to use to dig for further, relevant troubleshooting info in dovecot+fts?